Can anyone recommend a reasonably priced exhaust upgrade to give a nice deep burbling sound? What options exist? Which suppliers/models do people have experience of and how much did they pay? Also, are the options valid for the MoT/emissions test?
By the way the car is a '98 UK Impreza turbo.

 

A lot depends on the type and volume of noise you are looking for.

LOUD:
- Blitz Nur Spec
- TSL Tiphoon (I owned one and it was too loud for me on the motorway)
- 5Zigen

Loud but not deafening:
- Afterburner Vortex
- Ninja
- Magnex Oval (I owned one and it was a nice burble and good roar on acceleration)

Nice burble, fairly loud on acceleration:
- Hayward and Scott Original Scooby Design (putting mine back on)
- Scoobysport design (taking off and replacing with H&S)

As you can see I've owned a H&S, Magnex, TSL and Scoobysport and I'd rate them in that order in terms of build quality, although there isn't much between them TBH.

They're all about the same price, expect to pay around £275 new and £125-£150 second hand.

If you are only replacing the back box and possibly centre pipe, you won't have any MOT problems. If you start taking out cats you will need to think about the MOT, (removing cats will also increase the volume of the exhaust - and make it MUCH better ).

 

Try blueflame performance theyr'e in skelmersdale north on m6 liverpool area.
I had a full system decat inc downpipe last year on one for about £300 and that had a lovely deep sound, lots were impressed.